1. Field of the Invention
Embodiments of the present invention generally relate to gradational insertion of an artificial lift system into a live wellbore.
2. Description of the Related Art
The oil industry has utilized electric submersible pumps (ESPs) to produce high flow-rate wells for decades, the materials and design of these pumps has increased the ability of the system to survive for longer periods of time without intervention. These systems are typically deployed on the tubing string with the power cable fastened to the tubing by mechanical devices such as metal bands or metal cable protectors. Well intervention to replace the equipment requires the operator to pull the tubing string and power cable requiring a well servicing rig and special spooler to spool the cable safely. The industry has tried to find viable alternatives to this deployment method especially in offshore and remote locations where the cost increases significantly. There has been limited deployment of cable inserted in coil tubing where the coiled tubing is utilized to support the weight of the equipment and cable. Although this system is seen as an improvement over jointed tubing, the cost, reliability and availability of coiled tubing units have prohibited use on a broader basis. Current intervention methods of deployment and retrieval of submersible pumps require well control by injecting heavy weight (a.k.a. kill) fluid in the wellbore to neutralize the flowing pressure thus reducing the chance of loss of well control.